In recent years, an automatic transmission comprising an automated gear type transmission is widespread in view of low fuel consumption and drivability of a vehicle. As such an automatic transmission, the so-called twin clutch type automatic transmission is widely known. The twin clutch type automatic transmission has two clutches and multiple gear trains. Any one of the two clutches are selectively connected to an engine, and any one of the multiple gear trains are selected by a gear selection apparatus, so that the selected gear train connects between an output shaft of the selected clutch and an output shaft of the transmission. Then, one of the clutches is engaged, and another is disengaged to form a desired gear position (for example, see Japanese Patent Laid-Open No. 1994-221347).
In the twin clutch type transmission, the so-called pre-shift is executed as follows to shorten a time required for shifting, and to mechanically protect a rotation synchronization mechanism. Prior to determination and execution of the next shifting, a predetermined gear selection apparatus executes the pre-shift operation that connects between the output shaft of a currently disengaged clutch (which is not driven) and the output shaft of a transmission via a predetermined gear train in order to make the next shifting (gear position) stand by while keeping a currently executed shifting. As a method for selecting a predetermined gear for executing the pre-shift, a data table having the same structure as the so-called shift line for a throttle opening and a vehicle speed, is set in advance. Then, in accordance with an amount of operation of an accelerator by a driver, an up shift prediction area or a down shift prediction area is determined to select a pre-shift gear (for example, see Japanese Patent Laid-Open No. 1998-318361).